Defer syncing TopSites with history until the first tab closure

chrome/browser/win/jumplist.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_WIN_JUMPLIST_H_
 #define CHROME_BROWSER_WIN_JUMPLIST_H_
 
 #include <stddef.h>
 
 #include <list>
@@ skipping 229 matching lines @@
   base::OneShotTimer timer_most_visited_;
 
   // Timer for requesting delayed updates of the "Recently Closed" category of
   // jumplist.
   base::OneShotTimer timer_recently_closed_;
 
   // Number of updates to skip to alleviate the machine when a previous update
   // was too slow. Updates will be resumed when this reaches 0 again.
   int updates_to_skip_ = 0;
 
+  // A boolean flag indicating if a session has at least one tab closed.
+  bool has_tab_closed_ = false;
+
   // Holds data that can be accessed from multiple threads.
   scoped_refptr<base::RefCountedData<JumpListData>> jumplist_data_;
 
   // The icon file paths of the most visited links and the recently closed links
   // in the current jumplist, indexed by tab url, respectively.
   // They may only be accessed on update_jumplist_task_runner_.
   base::flat_map<std::string, base::FilePath> most_visited_icons_;
   base::flat_map<std::string, base::FilePath> recently_closed_icons_;
 
   // Id of last favicon task. It's used to cancel current task if a new one
   // comes in before it finishes.
   base::CancelableTaskTracker::TaskId task_id_;
 
   // A task runner running tasks to update the JumpList.
   scoped_refptr<base::SingleThreadTaskRunner> update_jumplist_task_runner_;
 
   // A task runner running tasks to delete JumpListIcons directory and
   // JumpListIconsOld directory.
   scoped_refptr<base::SequencedTaskRunner> delete_jumplisticons_task_runner_;
 
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<JumpList> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(JumpList);
 };
 
 #endif  // CHROME_BROWSER_WIN_JUMPLIST_H_